1. Field of the Invention
The present invention relates generally to electromechanical detection devices, and more particularly, to a detector for permanent installation with an air conditioning or heat pump system for conveying to the operator when the pressure of refrigerant therein drops below an acceptable pre-determined range, and when the air pressure within associated H.V.A.C. ducting drops below a threshold value indicating replacement of the air filter is required.
2. Description of the Prior Art
Typical refrigerant devices use a refrigerant such as freon, which can leak out of the system over a period of time or have its flow impeded by clogged evaporator and/or condenser plumbing. The resulting loss in refrigerant initially results in the compressor having to function for extended periods of time to compensate for the loss, resulting in higher electrical bills and reduced system effectiveness. Eventually, the system will cease to function at all. Dirty air filters cause an additional problem, as the flow of air through the evaporator is diminished over time in proportion to dirt accumulation, likewise resulting in loss of system efficiency. In commercial applications in air conditioning installations such as hotels, where each room has its own air conditioning unit, the hotel management normally has no knowledge of system degradation until the hotel guest advises the management that the air conditioning is not functioning. By this time, the air conditioning may have been running inefficiently for an extended period of time.
Accordingly, it would be highly desirable for the housekeeping department to be able to keep advised of the operating condition of the air conditioning systems in each room, without having to resort to extensive maintenance procedures. By employing a detector which may be easily mounted in each room and permanently attached to the air conditioning system, housekeeping can keep abreast of precisely when an individual air conditioning unit requires service. Moreover, by incorporating a magnetically actuated reed switch in the device, it cannot be turned on by hotel guests, but only by the appropriate personnel who have a magnet.
Devices for sensing loss of refrigerant in a refrigerant system are known in the art. U.S. Pat. No. 3,508,236, issued to Adams, discloses a fluid pressure warning device for electromechanically alerting the operator of low refrigerant pressure. U.S. Pat. No. 2,230,961, issued to Lewis, discloses a leak alarm for refrigeration systems, and U.S. Pat. No. 4,612,775, issued to Branz, et al., teaches the use of a refrigeration monitor and alarm system for displaying various system parameters.
None of the foregoing references describe a refrigerant and air pressure loss detector which may be easily mounted in the hotel room or in combination with a central air conditioning unit, and selectively actuated by a magnetic reed switch.